FICHES D’IDENTIFICATION DU ZOOPLANCTON Edittes par J. H. F-RASER Marine Laboratory, P.O. Box 101, Victoria Road Aberdeen AB9 8DB, Scotland

FICHE NO. 158

SCYPHOMEDUSAE OF THE NORTH ATLANTIC (2)

Families : Pelagiidae Ulmaridae Rhizostomatidae

by F. S. Russell Marine Biological Association The Laboratory, Citadel Hill Plymouth, Devon PL1 2 PB, England

(This publication may be referred to in the following form: Russell, F. S. 1978. Scyphomedusae of the North Atlantic (2) Fich. Ident. Zooplancton 158: 4 pp.)

https://doi.org/10.17895/ices.pub.5144 Conseil International pour 1’Exploration de la Mer Charlottenlund Slot, DK-2920 Charlottenlund Danemark

MA1 1978 2

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6 5 Figures 1-6: 1. noctiluca; 2. Chtysaora hysoscella; 3. Cyanea capillata; 3'. circular muscle; 4. Cyanea lamarckii - circular muscle; 5. Aurelia aurita; 6. Rhizostoma octopus. 3

Order S E M AE 0 ST0 M E AE

Gastrovascular sinus divided by radial septa into separate rhopalar and tentacular pouches; without ring-canal.

Family Pelagiidae Rhopalar and tentacular pouches simple and unbranched.

Genus Pelagia PCron & Lesueur Pelagiidae with eight marginal tentacles alternating with eight marginal sense organs. 1. Pelugiu nocfilucu (ForskB1). Exumbrella with medium-sized warts of various shapes; marginal tentacles with longitudinal muscle furrows embedded in mesogloea; up to 100 mm in diameter.

Genus Ptron & Lesueur Pelagiidae with groups of three or more marginal tentacles alternating with eight marginal sense organs. 2. Chrysuoru hysoscellu (L.). Exumbrella typically with 16 V-shaped radial brown markings with varying degrees of pigmentation between them; with dark brown apical circle or spot; with brown marginal lappets; 24 marginal tentacles in groups of three alternating with eight marginal sense organs.

Family Cyaneidae Gastrovascular pouches branched ; marginal tentacles arising from subumbrella surface at a distance from umbrella margin.

Genus Cyanea P6on & Lesueur Cyaneidae with radial and circular muscles on subumbrella; with eight adradial groups of marginal tentacles arranged in more than one row; with eight marginal sense organs. 3. Cyuneu cupillutu (L.). Coronal and radial muscle folds with pit-like intrusions from gastrovascular sinus; 13-15 coronal folds between radial septa; average numbers of marginal tentacles in each group 70-150 or more; terminal ramifications ofgastrovascular sinus pouches without anastomoses; colour usually yellowish brown or reddish; diameter of umbrella usually 300-500 mm, up to 2000 mm. 4. Cyuneu lumurckii Ptron & Lesueur. Coronal and radial muscle folds without, or OCCaSiOMllY with only few, pit-like intrusions from gastrovascular sinus; 16-20 coronal folds between radial septa; average numbers of marginal tentacles in each group 40-60; terminal ramifications of gastrovascular sinus pouches without anastomoses; colour pale yellow to bright blue; diameter of umbrella 60-150 mm, up to 300 mm.

Family Ulmaridae With gastrovascular system of unbranched and branched radial canals with varying degrees of anastomosis; with or without sub- genital pits.

Subfamily Aureliinae Ulmaridae with small marginal tentacles and lappet-like structures arising from exumbrella slightly above umbrella margin; with simple and branched radial canals with little or much anastomosis; with ring-canal; with subgenital pits.

Genus Aurelia Lamarck Aureliinae with umbrella margin divided by 8 or 16 marginal clefts; with four unbranched oral arms; with anastomosis between a few or all of the radial canal branches. 5. Aurelia uuritu (L.). Umbrella with eight simple marginal lobes; oral arms as long as umbrella radius, with thick firm mesogloea and much-crenulated lips with many small tentacle-like processes along their margins; adradial canals unbranched; perradial and interradial canals with primary canals unbranched, but with branches from their bases which branch successively towards umbrella margin having only few anastomoses; diameter of umbrella usually up to 250400 mm. 4 Order R H I Z 0 STO M E AE

Without marginaI tentacles; manubrium with lips branched to form eight oral arms each with numerous mouth openings.

Family Rhizostomatidae Rhizostomid medusae with “scapulettes” or “epaulettes” on manubrium; with single terminal club on each of eight oral arms.

Genus Rhizostoma Cuvier With small epaulettes on base of manubrium; each oral arm with single club-shaped terminal appendage; usually with clearly defined main ring-canal from which arise intracircular coarse-meshed arcade networks of canals. 6. Rhirostoma octopirs (L.). With usually an average of ten velar marginal lappets in each octant; terminal clubs of oral arms with- out thin basal stalks.

FURTHER INFORMATION ON DISTRIBUTION IDENTIFICATION Pelagia is a warm temperate oceanic with direct develop- 1. : Broch, 1913, p. 17, (as Pelagiaperla). ment and only occurs in coastal areas when drifted in. Aurelia is Kramp, 1924, p. 46. Bigelow, 1928, p. 517. Russell, 1970, a cosmopolitan coastal and estuarine species. The other four p. 71. species are coastal, Cyanea capillata extending farthest north. 2. : Russell, 1970, p. 87. Gulfof Bothnia...... 5 3. Cyanea capillata: Thiel, 1962, p. 277. Russell, 1970, p. Gulf of Finland...... 5 106. Baltic proper...... 395 4. Cyanea lamarckii: Russell, 1970, p. 127. Belt Sea ...... 395 5. Aurelia uurita: Russell, 1970, p. 140. Kattegat ...... 2,3,4,5,6 6. Rhirostoma octopirs: Thiel, 1965, p. 37. Russell, 1970, Skagerrak ...... 4,596 p. 173. Northern North Sea...... 1,2,3,4,5,6 Southern North Sea ...... 1,2,3,4,5,6 English Channel (eastern)...... 1,2,4,5,6 English Channel (western)...... 1,2,4,5,6 Bristol Channel & Irish Sea...... 1,2,4,5,6 S. and W. of Ireland...... 1,2,4,5,6 Faroe-Shetland area...... 3,495 Faroe-Iceland area...... 3,4,5 Norwegian Sea...... 395 Barents Sea ...... 3,5

REFERENCES BICELOW,HENRY B., 1928. Scyphomedusaefrom the Arcturus RUSSELL,F. S., 1970. The Medusae of the British Isles. Vol. 11. Oceanographic Expedition. Zoologica, N.Y., 8, 10: 495- Pelagic , with a supplement to the first volume 524. on Hydromdusae. Cambridge University Press, 271 pp. BROCH,HJALMAR, 1913. Scyphomedusae from the “Michael THIEL,MAX ECON, 1962. Untersuchungen zur Artfrage von Sars” North Atlantic Deep-sea Expedition 1910. Rep. Cyanea lamarckii Per. et Les. und Cyanea capillata L., Abh, scient. Results Michael Sars N. Atlant. deep Sea Exped., Verh. naturw. Ver. Hamburg, 1961, N.F. 6: 277-293. 3 (1) : 1-20. THIEL,MAX ECON, 1965. Untersuchungen zur Systematik der I(RAMP, PAULL., 1924. Medusae. Rep. Dan. oceanogr. Exped. Gattung Rhizostoma. Abh. Verh. naturw. Ver. Hamburg, Mediterr. 1908-10 Medit. adj. Seas, 2, Biology H 1, 1-67. 1964, N.F. 9: 37-53.

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